Wainwright (groin) will begin a rehab assignment with Double-A Springfield on Wednesday, Derrick Goold of the St. Louis Post-Dispatch reports.
Wainwright was initially expected to begin his rehab assignment Tuesday, but giving him an extra day off will allow him to throw a few more pitches Wednesday. Moving back to Wednesday will also line Wainwright up to pitch the same day as Jake Woodford, whose rotation spot he's likely to take once activated form the 15-day injured list. It's not clear how many rehab outings Wainwright will require, but he's on track for a return before the end of the month.